Dropped frames caused by subtitle rendering

I don’t think VideoPlayer moved far enough with v18 as expected. So some of the old Kodi limitations still exist.

I’ll try and work around them

I will do some testing tomorrow with „dirty regions“ in advancedsettings, While I was using the libreelec box until the sync issue was fixed, I did alot of testing on other small issues and had some promising result with one particular setting. So I am hoping to get the same effect on the Vero 4k.

I’ve never seen this issue before until the other night when I was watching the first Avengers movie with my children.
There were a couple dropped frames right before the first subtitles were displayed.
That brought me here where I found this thread.
Interesting read.
Unfortunately I was unable to duplicate the issue.
Every attempt after the initial veiwing played smoothly, even with statistics on screen.

I watch a ton of 1080p Remux, Web-DL and encodes mostly with muxed in srt subtitles and never had this issue. Would be interesting to know what triggers it. Maybe only PGS maybe 4k ? Or some sort of combination of it

PGS subtitles, no matter which resolution. But it seems to be a lot more severe with 4K.

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Whats interesting is that i don’t have this issue with my Pi 3 when iam using OMX Player instead of MMAL. I don’t understand why the old OMX Player has no problems with it but MMAL does?

This topic is related to the Vero rather than the Pi. MMAL uses more resources, so is to be expected.

Yes but the RP 3 was mentioned above thats why i tested it (Avatar with PGS Subs) and was surprised that OMX didnt stutter but MMAL did.

The issue still persists, that is frame drops the first time a subtitle is displayed (SRT @ Vero 4k). I kind of accepted that and it doesn‘t bother me much anymore… though if it disappears sometime in the future, that would be nice too :wink:

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I’m looking in to this but was using PGS as an initial test


Sometimes when there is nothing spoken for a longer time, a nee frame drop may occur as well when the next subtitle appears… seems like the stuff rendering the subtitle offloads after a certain amount of time as well.

Could you add a feature (with on/off switch in settings) that always loads the module for subtitles and always keeps it active? The drops for SRT seem to be purely a result of Kodi loading it during playback (and possibly after longer time of no subs during playback). I think you mentioned something like that before.

It doesn’t really work like that.


I experience this issue since 2017 when I switched from pi to vero 4k.

Now I have a vero 4k and a vero 4k + and both have frame drops with srt subtitles. Playing 1080p or 4k videos, it happens all the time


This should be solved in 4.9, where we have updated the GPU driver.


I’m having some easily-repeatable massive frame drops in anime with subtitles on, e.g. Attack on Titan on my 4K+. It’s hilariously bad at times, especially during the intro for the show with the fan subs on. As soon as I turn the subs off the frame rate is silky smooth. The files are HEVC MKV (ASS-type subs). No issue playing these on my phone, iPad etc.

Is this issue still being worked on?

Can you share a sample of said file?

A sample would be good. I’ll then look at this under 4.9.

Sent you a sample, Sam. Cheers!

So what I wanted to say is that the issue persists. First time a sub is rendered and during a movie, whenever subs are rendered after a longer period of time without any talking.

I have to say I am actively looking to replace my Vero 4k because the issue is just so annoying as someone who uses subs regulary.

I could live with the first stutter the first time subs are rendered but somehow somethings falls asleep when there is a longer period of sub inactivity and whatever that is, when it then wakes up it causes stutter again.

Isn‘t it possible to add an option that would send fake and constant but non visible subtitle info, so whatever „it is“ it always keeps active. I don‘t care about higher cpu/gpu use overall, I want a smooth viewing experience.

I say this because if I would watch a movie with people constantly endlessly babbling, I would have no problems but beside the first frame drop the first time someone opens his mouth. Heck if what I suggested above is possible, the first frame drop would be the very first frame of the movie and not detectable.

Ok maybe there was a different problem after all.

I had applied the change to my advancedsettings.xml regarding algorithmdirtyregions = 0

I did this using Easy Advanced Settings Addon. It didn‘t really have any effect when I did this ober a year ago…

… however the tool never wrote the lines, so I just did it manually via ssh, which is a better idea anyway.

And what can I say? I had no frame drops on the next files I played, even when subs were first time rendered. I will continue to monitor the issue but hopefully that was the solution.